#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

typedef struct TreeNode {
	int data;
	struct TreeNode *left, *right;
} TreeNode;

TreeNode n1 = { 27,  NULL, NULL };
TreeNode n2 = { 34,  NULL, NULL };
TreeNode n3 = { 5,  NULL, NULL };
TreeNode n4 = { 7,  NULL, NULL };
TreeNode n5 = { 78,  NULL, NULL };
TreeNode n6 = { 20,  NULL, NULL };
TreeNode n7 = { '+',  &n1,  &n2 };
TreeNode n8 = { '*', &n7, &n3 };
TreeNode n9 = { '-', &n5, &n6};
TreeNode n10 = { '/', &n4,  &n9 };
TreeNode n11 = { '-', &n8,  &n10 };
TreeNode *root = &n11;

int get_height(TreeNode *node)
{
	int height = 0;
	if (node != NULL)
		height = 1 + max(get_height(node->left),
			get_height(node->right));
	return height;
}

int get_leaf_count(TreeNode *node)
{
	int count = 0;

	if (node != NULL) {
		if (node->left == NULL && node->right == NULL)
			return 1;
		else
			count = get_leaf_count(node->left) +
			get_leaf_count(node->right);
	}
	return count;
}

int get_node_count(TreeNode *node)
{
	int count = 0;
	if (node != NULL)
		count = 1 + get_node_count(node->left) +
		get_node_count(node->right);
	return count;
}

inorder(TreeNode *root) {
	if (root) {
		int d = root->data;		// 노드 방문

		if(root->left != NULL || root->right != NULL)
			printf("(");
		inorder(root->left);	// 왼쪽서브트리 순회
		if (d == '+' || d == '-' || d == '*' || d == '/')
			printf(" %c ", d);
		else
			printf(" %d ", d);	
		inorder(root->right);	// 오른쪽서브트리 순회
		if (root->left != NULL || root->right != NULL)
			printf(")");
	}
}

double evaluate(TreeNode *root)
{
	if (root == NULL)	return 0;
	if (root->left == NULL && root->right == NULL)return root->data;
	else {
		double op1 = evaluate(root->left);
		double op2 = evaluate(root->right);
		printf("(%10lf %c %10lf)을 계산합니다.\n", op1, root->data, op2);
		switch (root->data) {
		case '+':	return op1 + op2;
		case '-':	return op1 - op2;
		case '*':	return op1 * op2;
		case '/':	return (double)op1 / (double)op2;
		}
	}
	return 0;
}

int main(void)
{
	printf("트리의 높이: %d \n", get_height(root));
	printf("트리의 단말노드 개수: %d \n", get_leaf_count(root));
	printf("트리의 전체노드 개수: %d \n\n", get_node_count(root));

	printf("순환호출로 중위 순회 \n");
	inorder(root);

	printf("\n\n");
	printf("수식트리 계산 결과: %lf\n", evaluate(root));
}